Secret Imagine single

John Lennon's Imagine, with original artwork by Jason Little.

Amnesty International UK has launched a campaign where 100 unique copies of John Lennon's "Imagine" single is available from ebay. The campaign is called Secret 7", where each pressing of the single was given a unique cover. The records come with an authentication slip.
There are also seven test pressings available,  featuring Yoko Ono's signature on the centre label. These come with an ink stamped Secret 7" blank sleeve, which is numbered 1-7/7 on the reverse.
Apart from the Imagine single, the project also has released the following other singles:

Chvrches - Clearest Blue
Etta James - At Last
Jack Garratt - Worry
The Jam - Art School
Max Richter - Dream 3
Tame Impala - The Less I Know The Better

Link: Ebay UK